Determination of Picogram Levels of Levodopa in Pharmaceutical Preparations and Biofluids by Flow-Injection Chemiluminescence

Abstract

An ultrasensitive method for determination of L-dopa at picogram levels by flow-injection chemiluminescence (FI-CL) as presented for the first time, based on the quenching effect of levodopa (L-dopa) on the luminol-lysozyme reaction. It was found that the decrement of CL intensity was linearly proportional to the logarithm of L-dopa concentration ranging from 3.0 to 7.0 × 103pg mL-1(R= 0.9967), with the limit of detection (LOD) of 1.0 pg mL-1(3σ). The proposed procedure was successfully applied to the determination of L-dopa in pharmaceutical preparations, human saliva, serum, and urine samples with the recoveries ranging from 96.7% to 104.3% and RSDs less than 4.0% (n= 5).

Quantitative NMR analysis of L‐Dopa in seeds from two varieties of Mucuna pruriens

“…8 Several methods have been described in the literature for the quantitative determination of L-Dopa in various biological samples and pharmaceutical preparations, such as spectrofluorometry, gas chromatography, high-performance liquid chromatography (HPLC), high-performance thin-layer chromatography (HPTLC) chemiluminescence, and electrochemical determination. [9][10][11][12][13][14][15] In comparison with these techniques, NMR spectroscopy in quantitative analysis has the advantage that the determination can be made by adding an internal standard without performing a calibration curve. This is because, when a quantitative NMR (qNMR) method is used, the area of each signal is proportional to the molar concentration of the compounds analyzed.…”

Voltammetric Determination of Levodopa Using Mesoporous Carbon—Modified Screen-Printed Carbon Sensors

“…There exists a parallel alteration of cognitive functions, due to the prefrontal cortex and hippocampus being affected [ 8 , 9 ]. Since dopamine cannot be administered directly because it does not penetrate the blood–brain barrier, L-DOPA is the appropriate precursor for reducing the symptoms of Parkinson’s disease [ 10 ]. Taking supplements based on this amino acid could prevent neurodegenerative diseases, its beneficial effects extending to stress and libido problems.…”

Review. Electrochemical sensors used in the determination of L‐Dopa

“…However, for patients with long‐term use and elevated concentrations of L‐dopa, there is an association with various side effects, such as loss of appetite, gastritis, insomnia, nausea and vomiting, dyskinesia, paranoia or even hallucinations 2,4,5 . A number of analytical methods are used for the determination of L‐dopa, such as high performance liquid chromatography, 6–9 electrochemiluminescence, 10 spectrophotometry, 11 flow injection analysis, 12 capillary zone electrophoresis, 13 and fluorescence methods 14,15 . Although these methods provide high sensitivity, a series of disadvantages could be identified, such as complexity, long testing time and high costs 16–19 .…”